Pollutant Concentrations

Air quality readings will be available hourly from 7am to 11pm. Air quality readings from 12am to 6am will be made available at 7am on the same day.

Readings on 21 Nov 2014

View reading for:

Region

24-hr Sulphur dioxide(µg/m3)

24-hr PM10(µg/m3)

1-hr Nitrogen dioxide(µg/m3)a

8-hr Ozone(µg/m3)

8-hr Carbon monoxide(mg/m3)

24-hr PM2.5(µg/m3)

North

2(1)

26(26)

47(-)

16(7)

0.4(4)

12(51)

South

7(5)

21(21)

52(-)

13(6)

0.5(5)

10(43)

East

3(2)

17(17)

22(-)

25(11)

0.3(3)

11(46)

West

4(2)

25(25)

52(-)

19(8)

0.6(6)

12(51)

Central

7(4)

18(18)

50(-)

32(13)

0.6(6)

11(44)

1-hr PM2.5 (µg/m3)b Readings on 21 Nov 2014

View reading for:

Time

1am

2am

3am

4am

5am

6am

7am

8am

9am

10am

11am

12pm

North

9

18

11

11

6

5

4

5

9

6

10

8

South

14

7

4

5

5

3

7

2

7

11

12

28

East

19

24

11

13

11

8

9

10

8

9

14

14

West

7

11

9

11

5

3

13

13

9

10

10

18

Central

14

16

11

7

5

5

7

7

11

9

8

14

Time

1pm

2pm

3pm

4pm

5pm

6pm

7pm

8pm

9pm

10pm

11pm

12am

North

8

12

12

8

17

18

22

15

22

16

24

-

South

9

17

20

9

9

27

12

10

7

6

6

-

East

6

13

9

9

14

16

6

5

10

6

8

-

West

12

12

18

14

16

16

17

20

14

14

14

-

Central

10

21

14

9

8

27

11

7

2

5

8

-

Note:a Sub-index for nitrogen dioxide is reported only when the 1-hr concentration equals or exceeds 1130 µg/m3.

b There is no sub-index for 1-hr PM2.5.

3-hr PSI Readings from 1am to 12am on
21 Nov 2014

Time

1am

2am

3am

4am

5am

6am

7am

8am

9am

10am

11am

12pm

3-hr PSI

52

53

51

47

35

28

26

28

34

35

40

50

Time

1pm

2pm

3pm

4pm

5pm

6pm

7pm

8pm

9pm

10pm

11pm

12am

3-hr PSI

51

53

52

52

51

54

55

54

49

44

45

-

Hourly updates of 3-hr PSI readings are provided from 7am to 11pm. The 3-hr PSI readings from 12am to 6am will be made available at 7am on the same day. The 3-hr PSI readings are calculated based on PM2.5 concentrations only.